kspace module needs to be reconfigured, tested, and documented

[James Antonaglia]

As a part of the 2018 hackathon, I took a close look at the kspace module to see what needs to be done to it to make it more user-friendly and versatile. I have attached a pdf that contains my suggestions. I can't attach this pdf to a comment on the original issue, so I apologize for making a new issue.

[Bradley Dice]

The kspace module has been removed. The FT calculations have been ported to pure Python in the euclid shape library.